Nonicing carburetor



, 2 f Pm/ P f 4 g i t M3 v O L M; C. BROWN NONICING CARBURETOR FledMarCh 2.7, 1943 May 15, 1945.

INVENTOR MORRIS CBROWN ATroR-NEY rig-id with throttle vshaft I0.

Patented May 1945 LNomclnd GARURE'roR Morris O. Brown, Brentwood, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware f Application March 27, 1943, Serial No. 483,805 y 1 claim. (c1. ,ce1-41a) This invention relatesto carburetors for internal combustion engines and consistsparticularly in novel means for preventing icing at the throttle Valve, particularly during idling.`

When a carburetor is idled in cold weather and before the engine heat hasreached normal,

' the moisture content 'of the air drawn through the carburetor frequently condenses and freezes adjacent and on the'upper surface and edges of the throttle because of the cooling effect due to expansion of the fuel and air upon passing-the throttle. idling port and cause the engine to stall. Various schemes for quickly heating the carburetor barrel adjacent the throttle excessively complicate the carburetor and are not Wholly satisfactory.

The main object Aof the present invention is to The icey thus formed may clog the` throttle return spring, being provided, as diagrammatically indicated at 38. An adjusting screw 39 mounted in crank 36 is disposed to engage' an abutment 4I) onA the carburetor barrel for limiting the clockwise movement of the throttle. Screw 39 is arranged to permit the throttle plate to'tightly closerduring normal idling, but

without jamming. A lip 42, 4bent inwardly from crank 36, provides a perm-anent positive stop to prevent wedging and damaging of the throttle plate.v Ifk desired screw 39 may beeliminated. An air by-pass 43 is provided around the throttle plate for supplyingL air, when the throttle is 1 closed, to'form la combustible idlingvmixture with provide simple, effective means rfor ypreventing let portion 8 controlled by a butterfly throttle valve 9 pivotally mounted on a shaft I0. A choker valve II is `pivotally.mounted in the air horn andcontrolled by anysuitable manual or automatic means. The carburetor is mounted on the riser portion I2 of the intake manifold I3 and above the usual hot spot I 4.

the fuel emittingfrom ports 32 and 33. The quantity of air by-passed may be adjusted by a valve screw 44, ythe screws 34 and 44 providing for-adjustment ofthe speed and richnessof the idling mixture.

The structure operates as follows: i During'normal idling when the throttle pla is tightly closed, a very rich mixture of fuel emerges from ports 32 and 33 and the air passing through by-pass 43 readily mixes with this fuel, because ofthe high suction posterior to the throttle, to form a properly combustible idling mixture. In present carburetors,l this extra air for idling is supplied around the edge of the throttle valve which is held slightly open during normal idling. Such air, upon passing around the throttle,natural1y expands and the moisture content thereof may condense and freeze. However, no such condensationand freezing can occur in the improved structure shown since prac- Adjacent the barrel is a fuel bowl 4I8 within `which fuel is maintained ata substantially constant level by the usual needle valve mechanism (not shown) controlled by ,a float I9. Fuel is supplied to the mixing'conduit through a meterring orice 20, controlledvby a metering pin 2l,

and a main fuel passa-ge 22 terminating in a fuel` nozzle 23 which opensinto the smallest venturi 1. Metering rod 2| is controlled by the throttle by means of a lever 24, a link `25 and an arm 26 Fuel for idling is supplied through passages and 3| terminating in idling ports 32 and 33. y Port 32 opens on both sides of throttle plate 9 when closed and `port 33 is provided with an adjusting screw 34.

On the end of vthrottle shaft II, opposite arm 26, thereis provided a second arm or crank 36' for Aconnection to the usual throttlev control Y linkage, shown in part at ,31,y the usual tically all of the idling air emerges into thev mixture conduit at av point substantially spaced from the idling ports and the throttle plate where ice ,I

crystals may be harmlessly carried to the cylinders. A slight amount of air may pass through port 32, but the moisture content in such a small quantity of air is insufficient to causeany substantial icing.

Various features of the carburetor may be modified within the knowledge of the art and the spe'- cie arrangement of the air by-pass may be varied just so long as the idling-air is kept away f from the idling port. The exclusive use of all modifications as come within the scope of the appended claim is contemplated.

Iclaim:

A non-icing, carburetor comprising a mixture conduit having a throttle therein, interconnected main and idlingfuelpassages discharging, respectively, anterior and posterior to said throttle when closed, means to move said throttle to suchy 2v' p *Y 2,376,228

a fully closedposition vas to` prevent a substan tial air flow for normal idling through said mixture conduit, xed stop means limiting closing of said throttle to a position to prevent jamming of said throttle against the conduit wall, a constantly open air by-pass extending around said throttle between portions of said mixture conduit spaced substantially on opposite sides of said throttle, the discharge end of said by-pass being at a point in said conduit substantially diametrically opposite to the normal idle oriiice for providing a combustible mixture during normal idling with the fuel from said idling passage. and means to Vary the effective size of said by-pass to adjust the idling speed of the engine.

MORRIS C. BROWN. 

